<?php
$uid = $node->uid;
$user = user_load($uid);
$username = ($user->profile_nickname) ? $user->profile_nickname: $user->name;
echo t('Submitted by !username on @datetime',
    array(
      '!username' => l($username, 'user/' . $uid),
      '@datetime' => format_date($node->created),
    ));
?>
